Elevating truck



Sept 26, m33 D. E. HENNEssY 1,928,490

vELEVA'I' ING TRUCK Filed May 16, 1952 5 Sheets-Sheet l inver-Nor.Daniel El-lennessy bywww AIB/S.

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Sept. 26, 1933. D. E. HENNESSY ELEVAT ING TRUCK Filedv May 16, 1932- 5Sheets-Sheet 3 lnvenToT Donie E. Hennessy byfewmw Ays Patented Sept.i933 y, nLnvA'riNe TRUCK n Daniel E. Hennessy, Watertown, Mass.,assigner to,` Lewis- Shepard Company, Watertown, Mass., `a corporationof Massachusetts Application May 16, 1932. Serial No. 611,476

i2 claims. (c1. 25e-.im

This invention relates toimprovements in ele- Y vating truckscomprising'a frame andload supporting means mounted thereupon adapted tobe raised relatively to the frame in such manner that 5 the truck, withthe load supporting means in lowered position, can be introduced beneatha loaded platform or skid, with means operable to raise theloadsupporting means, thereby lifting the platform or skid from thefloor and permit its transportation. i f

In usual trucks of this character the `load supporting means is eitherraised vertically relatively to the frame, or moved forwardly relativelyto the frame, the upward movement of the load supporting means beingcaused byparallel links,

cci-operating rever'sely inclined surfaces, or otherwise. Inelevatingtrucks of thetype` in which the load supportingl means is`moved rforwardly andr upwardly, a reverse movement is required to lowerthe load supporting means by moving it Vdownwardly and rearwardly. Thismanner of lowering the load is likely to cause'a great deal of damage toloads, such as bags of flour, cement, etc., by abrasion during kthedescent when contactingwith adjacent loads, and is subject to a greatdeal of complaint by users.

One of the objects of the present invention is to provide an elevatingtruck ,which comprises a wheel-supported frame, load supporting meansmounted thereon, and means for raising said load supporting means uponmovement thereof rearwardly relatively to said frame, including alifting lever and a thrust member connected thereto operable uponactuation thereof detachably to engage and to shove the load supportingmeans rearwardly. f f f Y By reason of this construction the load israised by moving backwardly and upwardly, and lowered 'by movingforwardly and downwardly,A so that during the descent `of the loaditmoves away from adjacent piles or loads and eliminates such abrasion.When a load thus deposited is relifted, there is always sufficient spacebetween 5 the load to be lifted and an adjacent pile or load to preventabrasion.A 'n

If loads are of such a nature that they `are not subject to abrasivedamage, and it wouldbe unn desirable to'lose floor space by spacing theloads as above described, the spacing can beeliminated and the loadsdeposited closeto each other by a light rearward pressure on the tonguewhen the loads are abutted and lowered. During such an operation thewheel support assumes all of the 5 longitudinal motion and the loaditself descends vertically. Upon re-lifting of the load the reverse orforward movement of the wheel frame permits the load to be raisedvertically, as will be obvious.

Another object of the invention is to provide a lifting truck in whichthe load supporting means is raised upon longitudinal rearward movementthereof relatively to the frame, with actuating mechanism which willrequire a minimum amount of head room. This is accomplished in thepresent invention by providing the steering post of the truck with earsextending upwardly there,- from a short distance, fulcruming thesteering tongue in such ears, and pivoting a thrust member upon thetongue, below the steering post,l with means for automaticallypositioning the thrust member to engage a'complementary abute ment uponthe front end of the load supporting means, and operable upon depression`of the tongue from upraised position first to engage the abutment, andupon further downward movement of the tongue to shove the upper end ofthe load supporting means rearwardly relatively to the steeringmechanism and frame. When the steering tongue is swung `downwardly tonormal steering position and the load supporting means lifted in itsuppermost position, the ears upon the steering post Vare only slightlyabove the level of a low dash board upon the load supporting means. Byreason of this construction the truck re quires very much less head roomthanY trucks heretofore constructed. Furthermore, since the loadsupporting means is moved rearwardly to raised position, sumcientleewayis provided to permit the tongue, when at a convenient height forsteering, to be swung through a complete circle, S-degrees, withoutengaging the. usual load upon the truck. A l A further object of theinvention is to, provide a truck in which injury to the operator, by theexertion of a full liftingeffort upon handle, is prevented.

In usual trucks in which the load supporting means is moved forwardly toraise it from the frame, means, such as a hooked pawLdetachably connectsthe tongue to the load supporting means. If suchA means are not properlyengaged or re leased by momentaryrelief of the pressure upon the tongue,the handle'and load supporting means become disconnected,A so that whenthe operator' again exerts his full lifting power upon the tongue he islikely to Vfall backward and be injured. Many operators have beenseriously injured in this manner. In the present construction thisisprevented by automatically positioning the thrust member so' that itwill invariably engage the a loadless abutment upon the load supportingmeans upon depression of the tongue and providing such detachableconnection therebetween that the thrust; member will be maintainedconstantly in engagement with the load supporting means by the weight ofthe load during the lifting operation.

A further object of the invention is to provide an elevating truck ofthis character with a gravity-actuated locking pawl having a flatshoulder engaging a rotatable member when in locked position and whichcan be easily unlocked by the rotation of such member.

Another object of the invention is to provide an elevating truck inwhich the thrust member is normally supported in position to engage thelload supporting means upon depression of the tongue, but which willpermit free steering movement of the tongue.

Another important object of the invention is to provide an elevatingtruck having a load supporting means movable longitudinally relativelyto the frame, with inclined fluid-operated means for checking thedescent of the load in which all possible leakage of fluid will notimpair the efficiency of the check.

These and other objects and features of the invention will more fullyappear from the following description and the accompanying drawings, andwill be particularly pointed out in the claims.

In the drawings:

Fig. 1 is a plan view of an elevating truck embodying the preferredformv of the invention;

Fig. 2 is a side elevation of the same showing the load supporting meansin lowered position;

Fig.-3 is a front end View of the same;

Fig. 4 is a side elevation of the truck showing the load supportingmeans in elevated position with the tongue upraised and illustrating indotted lines the position of the tongue and thrust member during theelevating movement of the load supporting means; and,

Fig. 5 is an enlarged detail longitudinal sectional view of the pistonof the release check illustrating in dotted lines the cylinder of thecheck in which the piston operates.

The elevating truck illustrated in the accompanying drawings comprises amain frame having parallel side bars 1 and 2, having their rear endsbent toward each other at right angles and connected together by a plateoverlapping and welded to the abutting ends thereof, and connected attheir front ends by an arch-shaped head 3 having an integral centralVboss 4 in which the steering post 5 of the steering mechanism isrotatably mounted. The steering mechanism comprises a cylindrical head 6in which the steering post is secured and has an upper enlargedilange '7which engages the lower end of theboss 4. An axle 8 extends horizontallythrough and is fixed to the cylindrical portion of the steering head,and steering wheels-9 and 10 are mounted upon the respective ends of theaxle.

The steering post extends upwardly into and is welded to the base 11 ofa bracket having ears 12 and 13 extending upwardly therefrom a shortdistance. The steering tongue 14 has a bifurcated head 15 the arms 16and 17 of which are fulcrumed upon a shaft 18 mounted in the ears 12 and13. A thrust membeilQ, preferably in the form of a rectangular bar, isfulcrumed upon a pivotal shaft 20 which is mounted in the lower ends ofthe bifurcated members 16 and 17 of the head of the tongue, and when thetongue is in upraised position normally rests upon the base 11 of thebracket in such position that upon forward swinging movement of thetongue the thrust member will engage a complementary abutment upon theload supporting means.

A spring 21, which is secured at one end to the thrust member near itsfree end and at its opposite end to a collar 22 upon the fulcrumed shaftof the tongue, serves to maintain the thrust member in position properlyto engage the complementary member upon the load supporting means duringthe lifting of the load caused by the depression of the tongue. Thespring is, however, operable when the load supporting means has beenraised to and locked at a predetermined height and the tongue thereafterraised automatically to disengage the thrust member from said abutmentand retain the thrust member in such position that it will permit freerotation of the steering tongue without interference with any other partof the truck.

The load supporting means comprises a frame having side bars 23 and 24corresponding to and preferably located directly above the side bars 1and 2 of the main frame. The rear ends 25 and 26 of the side bars 23 and24 are bent toward each other at right angles and their ends abutted.The abutting ends are connected together by a plate 2'7 overlapping theadjacent ends and secured to the respective portions 25 and 26 bywelding, as heretofore described in respect to the frame construction ofthe truck. A transverse girder 28, having a downwardly extending web 29and an integral upwardly extending reenforced member or dash board 30.connects the side members 23 and 24 in proximity to their front ends.

The load supporting means is connected to the frame by front and rearpairs of parallel links. The front pair of parallel links 3l are pivotedat their upper ends to ears 32 integral with and projecting forwardlyfrom the transverse girder 28 by stud shafts 33 which also extendthrough the front portions of the side bars 24 of the load supportingmeans. The lower ends of the front links 31 are pivotally mounted upon atransverse shaft 34 which is mounted in rearward extensions 35 of thehead 3 of the frame and which also extends through the side members 1and 2 of the frame. The rear parallel links are pivotally mounted attheir upper ends upon a shaft 36 which is mounted in the side bars 23and 24 of the load supporting means. The rear link mechanism comprises atwo-part frame consisting of pairs of parallel links 37 and 38 rotatablymounted upon the shaft 36 and welded to a sleeve 39 intermediate of saidlinks, and also to a sleeve 40 extending inwardly toward the center ofthe load supporting means.

The lower ends of the parallel links 37 and 38 are pivotally mountedupon a shaft 41 extending transversely across the main frame near itslower end, and mounted in the side bars 1 and 2 of the frame. The rearwheels 42 of the truck are mounted upon the shaft 41 between the links37 and 38. A spacing sleeve 43 is interposed between the inner links 38.

The'upwardly extending member or low dash board 30 of the fronttransverse girder 28 of the load supporting means is provided centrallywith a relatively narrow forward extension 44 which is re-enforced bywebs 45 integral with the transverse girder, and has a rounded forwardedge 46 providing an abutment to engage the re-entrant end 47 of thethrust member 19 which normally swung upwardly slightlybeyond verti- Viocal position and is held in this position by engagement of the`bifurcated extension of the `tongue with the base of ithe bracket uponthe upper end of the steering post. When in this positionthe free end ofthe thrust member` is separated a short distance from the co-operatingabutment upon the load supporting means, so that the steering mechanismcan be freely rotated to a complete circlefof S60-degrees. When itisdesired'to raise the load 'supporting means, the*` tongue is `swungdownwardly in substantially the central plane of the truck. Thisdownward depression of the tongue rst causes the reentrant abutment atthe end of the thrust memy movement ofthe load supporting meansrelatively to the steering mechanism andfframe.

Suitable means arev provided for locking` the load supporting meansY inraised position.

, the construction illustrated a novel locking means is provided whichcomprises a. gravity-actuated pawl 48 whichl is pivotally mounted at itsrear end upon one of the shafts 33 intermediate of the 'forwardlyextending ear 32 of the front girder of the load supporting means andthe side bar 'cci ' 24. When the load supporting means is inloweredposition the pawl 48 rests midway of its length (in upwardly inclinedposition as shown in Fig. 2) against a shaft-49fwhich is rotatablymounted in suitable ears 50 integral with and extending rearwardlyfromthe head 3 of the frame. The free end of the pawl 48 is cut away toprovide a notch presenting a shoulder 51 with an end portion 52projecting therebeyond.` The lower portion of the shoulder is beveled tothe under face of the pawl. The length of the pawl is such that when theload supporting means is moved rearwardly and is raised by the action ofthe parallel links to a predetermined height, slightly before `theparallel links have reached a vertical` position, the shouldered portionof the pawl will drop down into ysubstantially horizontalposition, asillustrated in Fig. 4, and will abut against the rotatable shaft 49,thereby preventing forward movement of the load supporting means andholdingfthe same in elevated position. The rotatable member 49hassecured to its opposite end an actuating member, such as a forwardlyextending `pedal 53, adapted when depressed to rotate the shaft, andthereby cause disengagement of the pawl by the rotating frictienalmovement of the shaft upon the abutting shoulder of the pawl. By reasonof this construction the pawl can be ydisengaged by very light pressureupon the pedal. y

Counterbalancingfmeans, suchvas a counterweight 54 secured to the shaft49 and extending rearwardly therefrom, serves to restore the pedal toupraised position when the foot is removed therefrom. e

` Afurther object of the invention, as above stated, is to providey aiiuideactuated dash pot or check mechanism for so restraining thedescent of the load supporting means as to prevent injury to the load,in which all'possible leakage of the duidr from the cylinder of thecheck will not limpairV the efficiency of the check. In usualconstructions in which an inclined dash pot is employed, the wearing ofthe' bushing, in which the piston of the dash pot is mounted, causes aleakage of the fluid from the cylinder of Sil the dash pot, and inasmuchas the extent of the n movement of the piston in the dash pot is alwaysthe same, such leakage of the liquid produces an air chamber between thepiston andthe remaining fluid in the dash pot, so that when they loadsupporting means is released itwill descend freely such distance as ispermitted by thefaccumulation of air between the liquid and the piston,and upon engagement of the piston with the incompressible fluid willproduce a distinct shock or jolt upon the load. The amount of this shockwill, of course, increasein proportion to the amount of fluid which-leaksfrom the dash pot during the repeated tiltings of the dash pot vasthe load supporting means is successively raised and lowered. Thepresent invention comprises a dash pot construction in which suchleakage is obviated. The dash pot or check of the present inventioncomprises a cylinder pivotally conk nected to the frame and a pistonconnected to the load supporting means in suchmanner that the dash potis always in an inclined position. The cylinder, however, is providedwith-a supplemental reservoir containing suflicient tiuidY to cause theliquid level therein to be of sufficient height to maintain the portionof the cylinder below the piston completely full at all times and at allinclinations of the rdash pot. y

In the preferred construction illustrated the dash pot comprises acylinder 55 having a closure 58 .at its lower end provided with ears 57which are connected by a pivotal rod 58 to a boss 59 which is integralwith and extends rearwardly from a transverse channel bar girder 60which is welded, or otherwise secured, at its ends to the side bars 1and 2 of the main frame. A cylindrical piston 6l is reciprocably mountedin the dash pot and has a piston rod 62, the upper end of which isconnected, preferably by a screw threaded connection, to a boss 63 upona collar 64 which is rotatably mounted upon the shaft 36 upon which theupper ends of the rear links are pivotally mounted, the collar 64 beinginterposed between the sleeves 40 of the frame forming the rear parallellink construction. In order to prevent impairment of the eiliciency ofthe dash pot by leakage of liquid from the portion of the cylinderbelowthe piston, the cylinder 55y is provided with an extension 65,preferably of rectangular cross section, forming a reservoir for theliquid; The lower portion, and preferably the longitudinal axis of thisextension, is at such an angle to the axis of the cylinder that itslower wall will be substantially horizontal when the load supportingmeans is in tially the same as that of the diameter of the cylinder, butthe vertical depth of the reservoir is considerably greater to enablethe end wall 66 of the reservoir to be equipped with a suitable boss 6'7to contain a bushing for the piston rod 62 and to enable said bushing tobe located at least above the minimum level of the liquid in thereservoir and cylinder. f

The front end wall 68 of the reservoir desirably is provided with a boss69 having a central aperture to provide a filling port which is adaptedto be closed by a plug 70. The liquid is introduced into the reservoiruntil the liquid level therein is noV of such height as to insurecomplete lling of the portion of the cylinder between the end of thepiston and the closed end of the cylinder irrespective of the angle orinclinationof the dash pot and its piston tothe horizontal, andpreferably is of a depth sufcient to submerge the upper end of thecylinder irrespective of its inclination, By thus maintaining theportion of the cylinder between the piston and the closed end of thecylinder completely filled at all times, no possible free or uncheckdmovement of the piston of the dash pot can occur.

. A preferred piston construction is illustrated in Fig. 5 having valvemechanism operable upon movement of the piston away from the closed endof the cylinder to vpermit liquid to ow freely from the upper portion ofthe cylinder or reservoir into the lower portion or the cylinder as theload supporting means is raised from the frame. A special valvemechanism is provided to restrict the passage of iluid from the lowerportion of the cylinder to the upper portion thereof during the descentor checking movement of the piston, and which will exert a resistance tothe escape of fluid under pressure from the lower portion of thecylinder substantially proportional to the weight of the load which isimposed upon the piston, thereby enabling the load supporting means todescend at substantially the same rate of speed irrespective of theweight upon it. This is of great importance in that it prevents loss oftime in the descent of the unloaded load supporting means, and alsoprovides means for properly cushioning the descent of the loadsupporting means irrespective of the weight of the load.

As illustrated in Fig. 5, the piston is of tubular construction and of asize slidably to t within the cylinder 55. A head 71, which is screwedinto the upper end of the piston body, is provided with a screw threadedaperture to receive a complementary screw threaded end of the piston rod62. A series of ports 72 in the head 7l permits the liquid to flowfreely into the chamber of the piston. The opposite end of the tubularbody is closed by a head 78 having one or more ports 74 provided with acheck valve, such as a ball 75, seated in a countersink in the head 73and adapted to permit liquid to flow from the chamber of the pistonfreely into the lower portion of the cylinder as the piston is movedaway from the lower head of the cylinder. The head 73 is provided with acentral screw threaded aperture in which is seated a plug 76 having anenlarged head portion 77 which abuts against the head 73. The ports 78in the head of the plug communicate with an annular groove 79 in saidplug adjacent its head and a radial port or ports 80 establishcommunication between the groove 79 and an axial bore 81. A valve stem82 has a reduced extension which is also screwed into the aperture inthe lower head 78 and is provided with an axial port 83 which extendsupwardly a considerable distance and communicates with radial ports 84.A common collar 85 is mounted upon the stem 82 adjacent to and abuttingagainst the head. A sleeve valve 86 is slidably mounted upon the stem 82and provided with a skirt 87 fitting and slidably mounted Aupon thecollar 85 and is of suicient length to provide a space 88 between saidcollar and sleeve. Small ports 89 extend longitudinally through thesleeve Valve 86. Another sleeve 90 is reciprocably mounted upon thevalve stem 82 and provided with a skirt 91 which ts upon the sleevevalve 86 and is of sufficient length to provide a chamber 92therebetween. A port or ports 93 extend through the sleeve 9D andcommunicate with a chamber 94 with a cap 95 having radial ports 96communicating with the chamber of the piston. A coil spring 97, which isinterposed between the cap and the head 98 upon the stern 82, servesnormally to force the cap and sleeves downwardly into the positionillustrated in Fig. 5.

In the operation of the device the upward movement of the piston, to theright, Fig. 5, permits uid from the upper portion of the cylin der orreservoir to now freely through the port 72 in the upper piston head andthe port 74` in the lower piston head into the lower portion' of thecylinder, the ball of the check valve being unseated by the fluid duringsuch movement. This permits the piston to move upwardlywith 'freedom asthe load supporting means is raised.

When the load supporting means is released from its raised position andbegins to descend. the piston 6l is forced downwardly in the cylinder55, thereby causing the valve 75 to close the port 74. Fluid from thelower portion of the cylinder is then forced through the ports 78 in theplug 76 into the annular recess 79 therein, thence through the radialport into the axial bore 81 from which it escapes into the axial bere83, of the stem 82. If no Very heavy pressiue is imposed upon the liquidin the lower portion of the cylinder, the liquid then iiows from theaxial bore 83 of the stem through the radial ports 84 into the chamber92, thence through the port 93 of the sleeve 90 into the chamber 94 ofthe cap 95 and from the chamber 95 'through the ports 96 into thechamber of the piston, from which it may escape through the port 72 intothe upper portion of the cylinder or reservoir. The restriction to theiiow of the liquid as it passes through the small ports and chambersabove described will impose suiiicient resistance to the movement of thepiston under light loads properly to cushion the descent of the loadsupporting means. When, howeveig'a sufliciently heavy load is imposedupon the load supporting means, the force with which the liquid isprojected through the axial bore 83 in the stem 82 will cause it to iiowthrough the port 89 in the sleeve 86, and thereby build up a pressure inthe chamber' 88 which will force the sleeve 86 longitudinally upon thestem against the resistance of the spring 97 and closes the port 84 moreor less, thereby further restricting the ow of liquid from the lowerportion of the cylinder to the chamber of the piston and consequently tothe upper portion of the cylinder.

By employing a spring 97 of suitable compressive strength, the extent ofmovement of the sleeve 86 in response to the pressure built up in thechamber 88 may be so controlled as to correlate the restriction of theport 84 and consequently the resistance to the escape of fluid underpressure to the weight of the maximum load as to cause a resistance tobe offered to the descent of the load substantially proportional to theweight of the load, so that the load supporting means will descend atsubstantially the same rate of speed irrespective of the load which iscarried by the load supporting means.

f Desirably a spring 99 is interposed between the end 66 of thereservoir and the collar 100 which is xedly secured to the piston rod toforce the piston rod downwardly when the load supporting means carriesno load.

It will be noted that in the construction above described the piston rodis pivotally connected to the shaft 36 upon which the upper end of therear link ymechanism is also pivoted, and that the closed lower end ofthe dash pot is pivotally connected to the cross girderGO'of the mainframe.

By reason of this construction resistance to the descent of the platformis applied directlyto the rear end portion-of the platform whichordinarily sustains the greater portion of the load and unduestrain uponthe side bars of the load supporting means `is thereby avoided. i

`It will Abe apparent that the elevating truck above described hasnumerous advantages over other trucks of the same type in that the frontend of the truck requires less head room, inithat the rearward movementof the load supporting meansv during the raising movement thereof isproduced by force imparted through a thrust member pivotally mountedupon the tongue and positioned to engage a complementary abutment inupraised position it can be readily swung out of engaging relation' tosaid: abutment to permit free steering of the truck. A l

By reason of the fact that the load SuppOrting means is moved rearwardlyrelatively to the steering mechanism during the raising of the loadrsup-- porting means, the load is moved asuiiioient distance away fromthe steering mechanism soV that when the load supporting meansVis'locked in raised position a much wider range" of steering movementofthe tongue is permittedwithout engagement with the load than intrucksheretofore constructed. The mechanism for looking the loadsupporting means in raised'position is oi a simple rigid character andmaintained in locked position by the tendency of the load SuplDOr'tingmean'sto move forwardunder the load upon it. inasmuch as the compressionresistance of metal exceeds the tensile strength thereof, this lockingmeans can be relatively light. The rotation of the rotatable member orrodwhich is engaged by the shouldered end of the locking means can beeasily accomplished and the locking mechanism released with a minimumeiort.

The construction of the dash pot mechanism above described is such as toavoid any possible leakage of huid which will impair the eiiiciency ofthe dash pot. The mechanism is of a simple construction and can be moreeconomically manufactured than usual trucks of this type.

It will be understood .that the particular ernbodiment of the inventiondisclosed herein is of an illustrative character 'and is notrestrictive, and that various changes in form, construction andarrangement of parts maybe made within the spirit and scope of thefollowing claims.

Having thus described the invention, what is claimed as new, and desiredto be secured by Letters Patent, is:y

l. An elevating truck comprising a main frame, load supportingmeans,means rfor raising said load supporting means upon movementthereof rearwardly relatively to said main frame includ- 'which isimposed f ing a tongue mounted to swing vertically and a thrustmemberpivotally mounted on said tongue and operable upon verticalswinging movement of said tonguedetachablyito engage and shove said loadsupporting means rearwardly. Y

2. An elevating truck comprising a main frame having steering mechanismincluding a tongue mounted to swing vertically,` load supporting means,means for raising said load supporting means upon movement thereofrearwardly relatively tosaid steering means, ,and a thrust membei'intermediate of said steering` mechanism and said loady supporting meansoperable upon de# pression of said tongue from upraised positiondetachably to engage and then to shove said load supporting meansVrearwardly.

,3. An elevating truck comprising a main frame having steering mechanismincluding a tongue mounted to swing vertically, load supporting means,means ior raising Vsaid load supporting Vmeans upon movement thereofrearwardly relaf tivelyvto said steering means, and a thrust memberpivotally connected to said tongue operable upon depression of saidtongue from upraised position detachablyto engage and then to shovesaidload supporting means rearwardly.

4. An elevating truck comprising a main frame having steering mechanismincluding a tongue mounted lto swing vertically, load supporting means,means for raising. said load supporting means upon movement thereofrearwardly relaf' tively to said steering means, a thrust memberpivotally connected tosaid tongue operable upon depression of saidtongue from upraised position detachably to engage and then to shovesaid load supporting means rearwardly, and means for normallypositioning said thrust member toengage a complementary abutment on saidload supportingY means upon depressionof said tongue from 115upraisedposition.

5. An elevating truck comprising 'a main frame having steering mechanismincluding a tongue mounted to swingvertically, load' supporting means,means` for raising saidloadsupporting means upon movement thereofrearwardly relatively to said steering means, athrust member i pivotallyconnected to said tongue operable upon depression of said tongue fromupraised position detachably toengage and then `toshove said loadsupportingmeans rearwardly, and resilient means normally positioningsaid thrust` memberto engage a complementary abutment on said loadsupporting means upon depression of said tonguel from upraised positionand to disengage said thrust member from said abutment when the tongueis raised from depressed position.

6. An elevating truck comprising a main frame having steering mechanismincluding a vertical steering post having ears extending a shortdistance above said frame, a tongue pivotally mounted on said ears, loadsupporting means connected to said frame by parallel links operable uponlongitudinal movement of said loadisupporting means rearwardly 'to raisethe same, a thrust member pivotally mounted on said tongue below thefulcrurn thereof, and means operable when the tongue is depressed fromupraised position to cause said thrust member detachably to engage acomplementary abutment upon said load supporting means, whereby furtherdepression of said tongue will shove the load supporting meansrearwardly.

7. An elevating truck comprising a main frame having steering mechanismincluding a vertical steering post having ears extending a shortdistance above said frame, a tongue pivotally mounted on said ears, loadsupporting means connected to said frame by parallel links operable uponlongitudinal movement of said load supporting means rearwardly to raisethe same, a thrust member pivotally mounted on said tongue below thefulcrum thereof, and means for so supporting said thrust member when thetongue is in upraised position as to permit unimpeded rotation of saidsteering mechanism, and selectively operable when the tongue is swungdownwardly from upraised position in a plane approximating thelongitudinal axial plane of the truck to cause said thrust memberdetachably to engage a complementary abutment upon said load supportingmeans and upon continued downward swinging movement of the tongue toshove said load supporting means rearwardly.

' 8. An elevating truck comprising a main frame having steeringmechanism including a vertical steering post having ears extending ashort distance above said frame, a tongue pivotally mounted on saidears, load supporting means connected to said frame by parallel linksoperable upon longitudinal movement of said load supporting meansrearwardly to raise the same, a thrust member pivotally mounted on saidtongue below the fulcrum thereof, a narrow abutment on said loadsupporting means centrally of the width thereof, a thrust memberpivotally mounted on said tongue below the fulcrum thereof of suchlength and so positioned as selectively to permit depression of thetongue from upraised position v in different vertical planes to causeload-lifting engagement with said abutment, or to prevent engagement ofsaid thrust member therewith, thereby permitting free steering movementof said tongue. Y

9. An elevating truck comprising a main framer Y load supporting means,parallel links connecting tating said rotatable member to disengage saidpawl therefrom by rolling contact therewith.

10. An elevating truck comprising a main frame, load supporting means,parallel links connecting said load supporting means to said frame,operable to raise said load supporting means upon movement thereofrearwardly relative to said main frame, means for locking said loadsupporting means in raised position before the parallel links havereached a vertical position comprising a cylindrical member rotatablymounted upon said frame, a co-operating thrust pawl pivotally mounted onsaid load supporting means normally resting upon said cylindrical memberand having a shouldered free end portion adapted to engage and abutagainst said rotatable member upon approach of said parallel links toapproximately vertical position, means for rotating said rotatablemember in a direction to disengage the shoulder of said pawl therewithby such rotative movement, and means for rotating said rotatable memberin the reverse direction.

11. An elevating truck comprising a main frame, load supporting means,and means for raising said load supporting means upon longitudinalmovement thereof relatively to said load supporting means, a dash potupwardly inclined from the horizontal having a piston pivotallyconnected to said load supporting means, a cylinder pivotally mounted onsaid frame and a reservoir extending from the upper end of said cylinderso constructed as to maintain a liquid level therein at such height asto insure complete filling of the portion of the cylinder below thepiston with liquid at all degrees of inclination of said dash pot.

12. An elevating truck comprising a main frame, load supporting means,and means for raising said load supporting means upon longi tudinalmovement thereofv relatively to said load supporting means, a dash potupwardly inclined from the horizontal having a piston pivotallyconnected to said load supporting means, a cylinder having a closedlower end pivotally mounted upon said frame and an open upper end, areservoir forming an extension of the upper end of said cylinder soinclined to the axis of said cylinder as to maintain a liquid level insaid reservoir above said piston at all degrees of inclination of saiddash pot cylinder.

DANIEL E. HENNESSY.

